·The CALLP operation is
used to call prototyped procedures or programs.

·It is a static call.

·If the keyword EXTPGM
is specified on the prototype, the call becomes a dynamic external call;
otherwise it will be a bound procedure call.

·If there is any error
in this call operation then the error can be traced with operator extender ‘E’
and LO level indicator which turns on in case of any error.

·If we don’t want to use
error indicator with operator extender ‘E’ even then we can trace the error by
using the built-in function %ERROR and %STATUS. For more information see chapter File and Program exception.

In
the NOMAIN modules we have used this keyword at procedure interface level. By
using this keyword only, the procedures will be visible to the outside world so
that it can be called using CALLP operation.